<template>
  <view>
    <!-- 搜索-->
    <view class="cate-search">
      <my-search></my-search>
    </view>
    <!-- 内容-->
    <view class="scroll-view-container">
      <!-- 左侧的滚动视图区域 -->
      <scroll-view class="left-scroll-view" scroll-y :style="{height: wh + 'px'}">
        <block v-for="(item,i) in cateList" :key="i">
          <view :class="['left-scroll-view-item', active === i ? 'active' : '']" @click="activeChanged(i)">
            {{item.cat_name}}
          </view>
        </block>
      </scroll-view>
      <!-- 右侧的滚动视图区域 -->
      <scroll-view class="right-scroll-view" scroll-y :style="{height: wh + 'px'}">
        <view v-for="(val,i) in cateList2" :key="i">
          <!-- 标题-->
          <view class="cate-lv2-title" v-if="val.children || val.children.length">/ * {{val.cat_name}} * /</view>
          <!-- 三级分类-->
          <view class="cate-lv2-list">
            <view class="cate-lv2-item" v-for="(value,index) in val.children" :key="index"
              @click="gotoGoodsList(value)">
              <!-- 图片 -->
              <image :src="value.cat_icon" mode=""></image>
              <!-- 文本-->
              <text>{{value.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
    import badge from '@/mixins/tabbar-badge.js'
  export default {
    data() {
      return {
        // 窗口的可用高度 = 屏幕高度 - navigationBar高度 - tabBar 高度
        wh: 0,
        cateList: [],
        cateList2: [],
        //默认选择的索引是 0 
        active: 0,
        // 距离顶端距离
        scrollTop: 0
      };
    },
    mixins:[badge],
    onLoad() {
      // 获取当前系统的信息
      const sysInfo = uni.getSystemInfoSync()
      // 为 wh 窗口可用高度动态赋值
      this.wh = sysInfo.windowHeight
      this.getCateList()
    },
    methods: {
      async getCateList() {
        const {
          data: res
        } = await uni.$http.get('/api/public/v1/categories')
        if (res.meta.status !== 200) return uni.$showMsg()
        this.cateList = res.message
        // 获取二级列表数据,默认展示第一个
        this.cateList2 = res.message[0].children

      },
      //改变点击的索引添加样式
      activeChanged(i) {
        this.active = i
        this.cateList2 = this.cateList[i].children
        // 在顶端的时候就为0.1(使他重新赋值,是页面重新加载),不为零的时候为0
        this.scrollTop = this.scrollTop ? 0 : 0.1
      },
      gotoGoodsList(i) {
        uni.navigateTo({
          url: '/subpkg/goods_list/goods_list?cid=' + i.cat_id
        })
      }

    }
  }
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;

    .left-scroll-view {
      width: 120px;

      .left-scroll-view-item {
        line-height: 60px;
        background-color: #f7f7f7;
        text-align: center;
        font-size: 12px;

        // 激活项的样式
        &.active {
          background-color: #ffffff;
          position: relative;

          // 渲染激活项左侧的红色指示边线
          &::before {
            content: ' ';
            display: block;
            width: 3px;
            height: 30px;
            background-color: #c00000;
            position: absolute;
            left: 0;
            top: 50%;
            transform: translateY(-50%);
          }
        }
      }
    }
  }

  .cate-lv2-title {
    font-size: 12px;
    font-weight: bold;
    text-align: center;
    padding: 15px 0;
  }

  .cate-lv2-list {
    display: flex;
    flex-wrap: wrap;

    .cate-lv2-item {
      width: 33.33%;
      margin-bottom: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;

      image {
        width: 60px;
        height: 60px;
      }

      text {
        font-size: 12px;
      }
    }
  }

  .cate-search {
    border-top: 0.5rpx solid red;
    z-index: 99;
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
  }
</style>
